Will be doing and will have done в английском языке

First study this example situation:

Tom is a football fan, and there is a football game on television this evening. The game begins at 7:30 and ends at 9:15. Ann wants to go and see Tom this evening and wants to know what time to come over:

Ann: Is it all right if I come over at about 8:30?
Tom: No, don't come then. I'll be watching the game on TV.
Ann: Oh. Well, what about 9:30?
Tom: Yes, that'll be fine. The game will have ended by then.

We use will be doing (future continuous) to say that we will be in the middle of doing something at a certain time in the future. The football game begins at 7:30 and ends at 9:15. So during this time, for example at 8:30, Tom will be watching the match.

Here are some more examples:

You'll recognize her when you see her. She'll be wearing a yellow hat.

This time next week I'll be on vacation. I'll probably be lying on a beautiful beach.

You can also use will be doing in another way: to talk about things that are already planned or decided:

I'll be going downtown later. Can I get you anything?

With this meaning will be doing is similar to am doing:

I'm going downtown later.

We often use Will (you) be -ing? to ask about people's plans, especially when we want something or want someone to do something:

"Will you be using your bicycle this evening?" "No, you can take it."

"Will you be passing the post office when you go out?" "Yes, why?"

We use will have done (future perfect) to say that something will already have happened before a certain time in the future. Tom's football game ends at 9:15. So after this time, for example at 9:30, the game will have ended. Here are some more examples:

Next year is Ted and Amy's 25th wedding anniversary. They will have been married for 25 years. (Now they have been married for 24 years.)

We're late. I guess the movie will already have started by the time we get to the theater.